Vienna Standard Mean Ocean Water
WTF?
Well, yes… there is a standard called the “Vienna Standard Mean Ocean Water” or “VSMOW”. It is an isotopic water standard defined in 1968 by the International Atomic Energy Agency.
Despite the somewhat misleading phrase “ocean water”, VSMOW refers to pure water (H2O) and does not include any salt or other substances in seawater. VSMOW serves as a reference standard for comparing hydrogen and oxygen isotope ratios, mostly in water samples. Very pure, distilled VSMOW water is also used for making high accuracy measurement of water’s physical properties and for defining laboratory standards since it is considered to be representative of “average ocean water.”
